Here is what I ate this noon:
It's easy and cheap and extremely tasty!

You need: an onion, ham or bacon, potatoes (or a few slices of
bread) grated cheese (I préfere swiss gruyère)
You can also add some fresh cream

Cook potatoes (with skin!) cut in half (you can leave the skin on or
take it off if you like)
OR take some slices of bread

Cut the onion and ham (bacon) in tiny pieces. Let the onion become
shiny (not gold) in some hot butter. Add the bacon (and garlic if
you like)

Put potatoes (or the bread) in a dish, put the onion and ham on top
of it, then the grated cheese. (if you are doing the potatoes you can
add some fresh cream, pepper and salt )
Let the cheese melt in the oven.
Bon apétit!
Inge